make_distrib: Add Python 3 support (see issue #2856)

tools/make_cmake.py

@@ -2,6 +2,7 @@
 # reserved. Use of this source code is governed by a BSD-style license that
 # can be found in the LICENSE file.
 
+from __future__ import absolute_import
 import os
 from file_util import *
 import sys